Refining of lubricating oils and simultaneous refining of gasoline type motor fuels therewith



2,342,630 ILs AND sIMULTANEoUs REFIN ING Feb. 29, 1944. w. E. FoRNEY REFINING OF LUBRICATING O OF GASOLINE TYPE MOTOR FUELS THEREWITH Filed Jan. 1, 1942 S .MMM wwf@ Dullllnl nllU Il- Nm.

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um Q Patented Feb. 29, 1944 UNITED STATES PATENT OFFICE REFINING OF LUBRICATING OILS AND SI- MULTANEOUS REFINING F GASOLINE TYPE MOTOR FUELS THEREWITH William E. Forney. Merchantvlle, N. J., assignor to Cities Service Oil Company, New York, N. Y., a corporation of Pennsylvania Application January 1, 1942, Serial N o. 425,266

(ci. lee-' se) Claims.

during their finishing refining treatment so that' the gasoline or motor fuel will not cloud or change color while in storage or deposit gum while being used in the engine.

Phosphorus pentoxide has been found to have a catalytic action as Well as a chemical combining action Withthe distillate hydrocarbons. It has also been found that the treatment involves reactions with the saturated as well as the unsaturated hydrocarbons. Some of the polymerization and alkylation compounds are not suitable as constituents of motor fuels on account of their boiling point, chemical reactivity, lead susceptibility and the like, but some of these compounds have been found to have properties that make them desirable as addition agents for lubricating oils. Some polymerization and alkalaticn products have good solvent properties for gums or resins or oxidation products that form in the lubricating oil while it is in use in an engine. Some hydrocarbon phosphorus products are advantageous for imparting drocarbons of thelubricating oil while in contact with vthe phosphorus pentoxide also promotes' reactions between the hydrocarbons of the lubricating oil and thepressure distillate. The compounds formed by all of these reactions are soluble largely in the lubricating oil and these compounds act as addition agents for modifying the properties of the lubricating oil, particularly its extreme pressure and oiliness properties, and anti-oxidation properties.

The primary object of the present invention is to carry 'out a combined and simultaneous rening treatment oflubricating oils and motor fuel. distillates to provide lubricating oils and motor fuels havingimproved and desirable properties.

A large portionof the alkylation, polymerization and phosphorushydrocarbon products resulting from the treatment of a mixture of lubricating oil and pressure distillate with phosphorus pentoxide is very desirable in the finished lubricating oil, so that the treatment is carried out to hold most of the reaction products in the lubricating oil and to separate them from the motor fuel.

Another object of the invention is to provide a carrier for the phosphorus pentoxide vtreatment of motor fuel distillates so that the distillate may be brought into intimate and continuous contact vwith the phosphorus pentoxide.l

In accordance with this object, one feature of the invention contemplates the'suspension of the v'phosphorus pentoxide is separated from the motor fuel lubricating oil mixture by settling or filtering. After being Washed with straight run naphtha, the phosphorus pentoxide is returned to the process to be again mixed with motor fuel and lubricating oil. v l

Another objectr of the invention is the use of a dispersing agent "with a finely divided catalyst (P205) to assist in securing an intimate'contact of the catalyst with oils being treated. Preferably saidV dispersing agent is an absorbent clay which also has clarifying and a catalytic action on the oil being treated.

Another object of the invention is to provide a process of simultaneously finishing a motor 'fuel gasoline and lubricatingfoil in a single distillation operation.

The'l'ar'g'e differences in boiling point between the motor fuel and the lubricating oil permits the motor fuel and lubricating oil to be fully separated from one another and at'the same time separated from the undesired reaction products formed in the treatment.

With these' and other objects and features in view, the invention consists', in thev improved method of rening lubricating oil and motor 'fuel hereinafter described and particularly deflned'in the appended claims.

The various features of the invention are illustrated in the accompanying drawing which shows diagrammatically a flow diagram illustrating the vvarious steps in the treatment of the lubricating oil and motor fuel.

A lubricating oil to be refined in accordance with the presentmethod preferably should be a lubricating oil from which has been removed the major portion of asphalt or resinous material that occurs therein. Accordingly the lubricating oil is given a preliminary treatment for the removal of asphalt and resin. To accomplish this, the lubricating oil, which may be either a distillate or a residual cylinder stock, is introduced through a line I into a heater l2 where its temperature is raised to approximately 150 F. The oil leaving the heater passes through a line I4 into which is introduced a precipitating solventpropanethrough the line I6. Approximately five volumes of propane are mixed with one volume of lubricating oil. The mixture vof oil and propane passes into a mixer |8 where is is thoroughly mixed, and the mixture flows through a line into a settling chamber 22. locity in the settling chamber 22 is preferably. slow so that the asphalt which has been precipitated by the propane will settle to the bottom of the chamber 22. The deasphalted oil leaves the `upper. portion of the chamber 22 through a line 24' and then passes through a heater v26 where its. temperature is preferably raised to approximately 200 F. This heated oil then flows through aline 28 wherein it is mixed with propane introduced through a line 30. The additional propane is` preferably measured `so that the volume of oil` passing out of the line 28 will consist of approximately one volume of oil to ten volumes of propane. This mixture flows into a mixer 32 where it is thoroughly mixed and then flows through a line 34 into a separating chamber S6. The velocity of the oil passing through the sepa- 'rator 36 is preferably slow so that any resin which hasy been-precipitated in the oil can settle to the' bottom' of the separator. The clean oil rises to the top of the separator and flows out through a line 38 to -a stripping still 40 wherein the propane is distilled overhead and separated from. the lubricatingA oil. Steam may be used in the stripper for assisting in the separation of the propane from the lubricating oil. rlhe lubricating oil leaves the bottom of the stripper 40 ary alcohols together with a dilute caustic soda solution for separating asphalt and resin from the lubricating oil.

The lubricating oil which preferably has been treated to remove the asphalt and resins may advantageously be utilized in the simultaneous refining of motor fuel. To accomplish this, lubricating oil' from the separator 44 is introduced through a line 4E into a mixer 48. At the same time gasoline or pressure distillate is introduced into the mixer through a line 50. Into the mixture of lubricating oil and distillate is introduced a mixture of phosphorus pentoxide and clay, through a line 52. This mixture of pressure distillate, lubricating oil, phosphorus pentoxide and flows through a line 54 to a pump 56 by which The oil vethe oil is circulated through a line 58 to a heater B0. The oil leaving the heater flows through a transfer line 62 into the bottom of a reaction chamber 64. The reaction chamber 64 is preferably provided with a stirrer by which the mixture of oils, clay and phosphorus pentoxide is kept in a uniformly mixed condition so that the entire mixture iiows upwardly through the reaction chamber and leaves the top of the reactionchamber through a line 66. This mixture flows into the top of a separator 68 wherein clay and part of the phosphorus pentoxide settles out of the oil mixture and may be removed through line T0. If the clay and phosphorus pentoxide are in suiciently active condition to be used again this material is pumped by pump 12 through a line 14 and returned to the line 58 to be again circulated through the heater` in the furnace G0. If the clay-phosphorus pentoxide mixture is highly exhausted then valves are arranged for vthe pump 'I2 to pump the mixture through a line 15 into a filter press 16. The partially claried oil-phosphorus pentoxide mixture flowing through the separator 68 leaves the separator vnear the top and flows. through a line 18 to the filter press 16. In the filter press the clay and phosphorusv pentoxide are separated from the oil mixture which consists of the lubricating oil and gasoline. If the color of the lubricating oil is not what is desired, the oil passing through the filter press iiows through a line passing through a cooler 82 into the top of a percolating, lter 84 where the oil percolates through a lter clay to secure the desired color, the gasoline being in contact with the lubricating oil passing through the filtering medium. The lubricating Oil-gasoline mixture leaving the lterl may pass directly into a surge tank 86 or the oil coming through the percolation lter may flow through a line 88 into the surge tank. This oil mixture then passes to pump 90 which forces it through a heater 94 into a bubble cap fractionating tower 96. The fractionating tower 96 is provided preferably with a large number of bubble plates in order to secure the desired fractionation. The end point gasoline passes overhead through a line 98 to a condenser and the condensed gasoline and any uncondensed gases then pass into a separator |02.

,A reilux return line |04 is connected with vthe separator |02 by which a part of the gasoline may be returned to the top of the tower to assist in the fractionation. A separating tray |06 is provided near the central portion of the bubble tower by which hydrocarbon fractions which preferably are polymers, together with phosphorus-containing hydrocarbons that are not desirable in the iinished gasoline on account of their higher-boilished lubricating oil is removed through the line l I8 located in the bottom of the bubble tower and passes through a cooler |20 to storage. A gas or stream stripper and-auxiliary heating coil may be used in the bottom of the bubble tower to assist in carrying outthe fractionation to remove gaso line and other undesired hydrocarbons. i

It may be necessary to have more than one separating tray, such as tray |06, in order to remove from the lubricating oil and the gasoline the fractions which are not desirable in them.

A portion of the phosphorus pentoxide circulated with the lubricating oil-gasoline mixture through the process is consumed in reacting with the hydrocarbons. rIhe phosphorus pentoxide does not react with a very large volume of the hydrocarbon material. Tests with Very large volurnes of hydrocarbon material have shown that for the average low-boiling lubricating distillate utilized, less than one per cent by weight of the phosphorus pentoxide used is consumed in the chemical reactions. acts predominately as a catalyst for promoting polymerization reactions as Well as some alkylation reactions.

The clay used in the process is preferably utilized as a carrier or dispersing agent, to assist in maintaining the phosphorus pentoxide in suspension in the lubricating oil-gasoline mixture. This clay can be ordinary filter clay or fullers earth, or it may be an acid-treated clay which is cornmonly known on the market as Filtrol. Some of the more reactive clays assist in decolorizing and polymerizing hydrocarbons in the lubricating oils as well as in the gasoline. However, the reactivity of the phosphorus pentoxide is depended upon for carrying out the reactions desired in the present process and the clay is used primarily as a dispersing agent. The P205 can be effectively used in the process without clay but the clay greatly facilitates the separation of the P205 from the oil and also aids in the revivification of the P205.

With some types of pressure distillates and lubricating oil, the amount of polymer, alkylation and other products formed tends, to foul the clay and phosphorus pentoxide and it is desirable to revivify the clay and phosphorus pentoxide before returning them to the process. In the drawing, a single filter press is illustrated but preferably two or more filter presses are used in practice so that one filter press may be used for revivifying the clay-phosphorus pentoxide mixture while the other filter presses are used in the filtering operation. To revivify the clay-phosphorus pentoxide mixture a iilter press is isolated from the circuit and then a washing solution which is preferably a gasoline or a low boiling hydrocarbon, such as pentane, butane or propane, is forced under pressure through the filter press to remove polymerized and terry materials that tend to foul the clay-phosphorus pentoxide mixture. The washed filter cake, while still in the filter', is dried by blowing with a stream of inert gas such as flue gas. It may then be removed from the press and broken up and returned in the form of a slurry with pressure distillate through a line 122 to the mixer 46. It is not necessary to form a slurry with the filter cake and this cake may be returned mechanically to the mixer 4B to again make up the slurry mixture.

In the treatment of most mixtures of lubricating oil and pressure distillate it has been found that 1/2 pound phosphorus pentoxide per barrel of pressure distillate-lubricating oil mixture is sumcient. However, if the hydrocarbons and the lubricating oil-gasoline mixture are such as to utilize a considerable quantity of phosphorus pentoxide, it may be necessary to raise the proportion of phosphorus pentoxide to one pound of phosphorus pentoxide per barrel of lubricating oilgasoline mixture.

In the preferred treating process, about three parts of clay for one part of phosphorus pentox- The phosphorus pentoxide' ide will give a satisfactory slurry. This clay, however, may vary from two to five parts of clay for one part of phosphorus pentoxide.

For the treatment of most distillate lubricating oils, particularly the neutrals, three to four volumes of pressure distillate' or gasoline is used for each volume of lubricating distillate. When the lubricating oil being treated is a residue oil or cylinder stock then two volumes of gasoline nay be used for each volume of lubricating resi In carrying out the main treating reaction to promote the polymerization, alkylation and phosphorus combination, the oil is circulated at a pressure of from o-275 pounds in a continuous circuit and the temperature leaving the furnace 60 and while passing through the reaction chamber 64 and separator 08 varies from 425" F. to 275 F. Itis preferred that the transfer temperature of the oil mixture should not rise above 425 and may be as low as 300 F. If the oil leaving the furnace has a temperature of 300 F., the oil leaving the separator -68 will probably be below 200 F.

Reference has been made in the description to the use of pressure distillate. This may also include a fraction of C3 and C4 hydrocarbons obtained during the stabilization of cracked gasoline or pressure distillate in the refinery. It is commonly known as stabilizer reflux since it is used for this purpose. This fraction may be used to replace the pressure distillate in whole or in part. If a mixture of C4 hydrocarbons and C3 hydrocarbons are utilized in the process then the distillation in the tower 96 will have to be modified to accurately separate these constituents from the lubricating stock.

The preferred form of the invention having been thus described, what is claimed as new is:

1. A method of simultaneously refining motor fuel distillate and lubricating oil comprising intimately mixing a motor fuel distillate containing unsaturated hydrocarbons with a lubricating oil and phosphorus pentoxide, heating the mixture and holding the mix-ture in intimate contact for an extended period'of time to cause the motor fuel distillate and the oil to react with P205 and allow reaction products to be dissolved in the lubricating oil, separating the phosphorus pentoxide from the oil mixture and fractionating the mixture to separate the motor fuel as an overhead cut and the lubricating oil together with dissolved reaction products as a bottom out.

2. The method defined in claim 1 in which the mixture of motor fuel-lubricating oil and phosphorus pentoxide advances as a continuous stream through each step of treatment.

3. The method defined in claim 1 in which the phospho-rus pentoxide separated from the lubricating oil-motor fuel mixture is again mixed with untreated lubricating oil and motor fuel to be reused in the treatment. n

4. The method defined in claim 1 in which phosphorus pentoxide is used in the ratio of 1/2 to 1 pound per barrel of lubricating oil-motor fuel mixture.

5. The method defined in claim 1 in which the oil mixture is heated to a temperature of 275-425 F.

6. The method defined in claim l in which the oil mixture is heated to a temperature of 275-425o F. and is held under a pressure of Z-275 pounds while the products are reacting.

7. The method defined in claim 1 in which two 'tofourvolumes of motor fuel are mixed with one Vvolume of lubricatingr oil.

fuel distillate and the oil to react with P205 and allow reaction products to be dissolved in the lubricating oil, separating the `clay and phosphorus pentoxide and `fractionating the 1ubricating oil-motor fuel mixture to separate them, said separated lubricating oil retaining dissolved reaction products.

10. The method dened in claim 9 in which undesired polymers and phosphorus compounds are separated from the motor fuel and lubricatingr oil in the fractional distillation step.

11. The method defined in claim 9 in which 13. The method defined in claim 9 in which they phosphorus pentoxide is used in the ratio of 1/2 to 1 pound of phosphorus pentoxide per barrel of lubricating oil-motor fuel mixture and approximately 3 parts of clay is used for each part of phosphorus pentoxide.

14. The method dened in kclaim 9 in which the phosphorus pentoxide and clay are separated by filtration and then revivifled by Washing with light oil Whereon they are prepared to be returned into the treating method for reuse.

l5. The method deiined in claim 9 in which resinous and asphalt constituents of lubricating o-il are substantially removed before the lubricating oil is mixed with the motor fuel and phosphorus pentoxide. WILLIAM E. FORlIEY` 

